Sulfophenylalkylsiloxanes and processes for their production are known. The U.S. Pat. No. 2,968,643 describes a reaction of chlorosulfonic acid and a phenethyltrichlorosilane to form an intermediate followed by hydrolysis of this intermediate. However, the by-product sulfuric acid resulting from the required excess of chlorosulfonic acid has to be separated. The U.S. Pat. No. 4,575,559 discloses a process for the production of sulfophenethylsiloxane in the presence or absence of solvent. The solventless process in a stirred vessel is very difficult to process because the reaction mixture becomes solid.
The object of the present invention was to provide a process for the production of sulfophenylalkylsiloxane or sulfonaphthylalkylsiloxanes which avoids solid intermediates formation and the formation of difficult to separate by-products and can be carried out in a conventional reactor system.